Hello,
We are about to start building a single-family house on short notice. For the heating system, we have chosen a ground source heat pump with deep boreholes.
However, we are quite uncertain about the type of heat pump and its capacity.
The house will be 143 m² (1540 ft²), with underfloor heating, insulation around the KfW 70 standard, a family of five, and a 200-liter (53 gallons) buffer tank.
The offers we have received range from 5.9 kW to 7.7 kW (Viessmann Vitocal 222) up to 8 kW. The required heat pump capacity calculated by the companies ranges from around 5 kW to 7 kW.
We often hear and read that the correct sizing of the heat pump is key to low heating and hot water costs. Due to the many different recommendations and calculations, we are now quite confused.
Who can help? What capacity should the heat pump have?
Is 5.9 kW sufficient? Would 7.7 kW be better?
Or should it be something else entirely?
We are about to start building a single-family house on short notice. For the heating system, we have chosen a ground source heat pump with deep boreholes.
However, we are quite uncertain about the type of heat pump and its capacity.
The house will be 143 m² (1540 ft²), with underfloor heating, insulation around the KfW 70 standard, a family of five, and a 200-liter (53 gallons) buffer tank.
The offers we have received range from 5.9 kW to 7.7 kW (Viessmann Vitocal 222) up to 8 kW. The required heat pump capacity calculated by the companies ranges from around 5 kW to 7 kW.
We often hear and read that the correct sizing of the heat pump is key to low heating and hot water costs. Due to the many different recommendations and calculations, we are now quite confused.
Who can help? What capacity should the heat pump have?
Is 5.9 kW sufficient? Would 7.7 kW be better?
Or should it be something else entirely?
waldorf schrieb:
....Therefore, heating engineers tend to equip systems with buffer tanks as a rule.... This usually has other reasons ;-)Furthermore, the type of "buffer tank" should be defined/clarified! Decoupled, series, or parallel. Most often, the latter is used. However, they hardly provide any buffering at all!
waldorf schrieb:
...If the heat pump is somewhat oversized, it can be well concealed through various settings... The reduced energy potential of the source due to the excessive cooling capacity cannot be corrected afterwards in this way.waldorf schrieb:
...Much more important is that the pipes of the underfloor heating are installed at close spacing of about 10cm (4 inches)....In modern buildings, with comprehensive optimization, pipe spacing ranges from 5 to 30cm (2 to 12 inches) within a building, depending on the room heating load.Best regards.